The prior art includes several methods and apparatus for minimizing or shrinking images. Many of these are described below.
U.S. Pat. No. 4,153,896 teaches compressing or expanding an image such as a symbol, character or text, in a first direction followed by compressing or expanding the image in a second direction. The image to be compressed or expanded is divided up by a grid defining a large number of square areas in the image wherein each area is represented by a clock cycle in each direction. The compression or expansion is accomplished by utilizing an averaging circuit which provides a signal indicating the value of the resulting image.
U.S. Pat. No. 4,503,469 teaches a picture image enlarging/reducing system wherein image magnification by a desired factor is achieved by first enlarging the image by a integer factor greater than the desired factor and then multiplying the enlarged image by a correction coefficient corresponding to the ratio of the desired factor to the integer factor.
U.S. Pat. No. 4,656,664 is directed to a method for reducing a binary image by rotating the image 90 degrees, removing one or more rows of bits, modifying rows adjacent to those removed rows to preserve selected information from the discarded line, rotating the image 90 degrees, removing additional rows, and modifying the line adjacent to each line discarded to preserve selected information from the discarded line, and repeating the steps of rotating, removing and modifying a predetermined number of times to achieve a reduction by a desired factor.
U.S. Pat. No. 4,675,830 is directed to a method for producing scalable contour data. The method stretches and compresses character contours to bring specified contour points into proper alignment with a bit map grid.
U.S. Pat. No. 4,809,083 is directed to enlarging or reducing an image at a desired magnification in a facsimile, copying machine or the like. This is accomplished by continuously varying a ratio of a reading resolution to a recording density.
U.S. Pat. No. 4,833,625 is directed to an image viewing station wherein digitized image data at any size from any different modalities is stored in an original format and can be magnified or minified for display to a user. Magnification is performed by producing interpolated image data for each pixel of a magnified image based on the weighted sum of grey levels present of each pixels four nearest neighboring pixels, including pixels from other rows or columns. Minification is performed by discarding pixels to achieve the desired minification.
U.S. Pat. No. 4,972,264 is directed to viewing and overscanned image by storing the original image as a first data block and generating a second data block for display by systematically removing every nth data element where n is an integer less the number of data elements in the first data block.